1. Field of the Invention
The present invention relates to an apparatus and process for forming a sheet of material having a uniform thickness and, more particularly, to an apparatus and process for forming a sheet of dough material, e.g., masa (corn-based dough), having a uniform thickness.
2. Description of Relevant Art
Apparatus for forming sheets of various materials, including dough or like food materials, by forcing the material through a gap or nip located between a pair of confronting rotating rolls are known in the art. In such apparatus, the supply or mass of dough is positioned above the gap formed between the confronting rolls, and the dough mass is forced into the gap with the rolls forming the dough into a sheet. The dough sheet may be cut or suitably portioned, and the portions are then processed according to the requirements for the desired product. For example, in the case of snack food products, the cut portions typically are baked or fried, seasoned, and then packaged.
Various problems exist in the production of sheeted materials using known sheerer apparatus. One significant problem involves the thickness of the final product (which may be, for example, tortilla chips). Product thickness is a characteristic which strongly influences the product attributes that are important to consumers. In other words, a product that is too thick typically is unacceptable or unsatisfactory to consumers.
In the known dough-sheeting apparatus mentioned above, variations or inconsistencies often exist in the rheology of the dough or masa mass that is fed into the gap between the rolls. These variations tend to exert substantial force and pressure against the rolls and cause the framework of the apparatus (which supports the rolls) to deflect, which results in fluctuations or changes in the size of the roll gap, which in turn results in variations in the thickness of the dough sheet and thus the final food product. One way this problem has been handled is for a person operating the sheerer apparatus to monitor such deflections and manually adjust the position of one of the rolls. These manual adjustments typically are required about 20-30 times during a seven hour period. In addition, and perhaps more significantly, manual adjustment of the roll gap size has proven unsatisfactory in that this method yields products about 30% of which are down-graded by consumers as being too thick. Such a large percentage of unsatisfactory product is unacceptable.
Furthermore, the need to provide the sheerer apparatus with a mechanism that permits continuous adjustment of one of the sheerer rolls increases the cost of the apparatus. In addition, the roll position adjusting mechanism increases the complexity of the apparatus and, consequently, reduces the mechanical reliability of the apparatus. A less reliable apparatus is prone to breakdowns which result in machine downtime and reduced overall efficiency. Accordingly, there is a need in the art for an improved apparatus for producing sheeted materials having a uniform thickness.